Question regarding run flats

Steedie

Steedie

Steedie

Man of Honour
Joined
29 Jun 2004
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Oxfordshire
Morning all,

On the way to work this morning cruising along at 30 and my run flat/tyre pressure indicator comes on. Not a nice thing to see in the morning, despite the fact it was 30, I had nowhere to pull over and it was only 8 miles until my destination anyway so I thought I'd crawl along until I got there

Anyway on arriving, I had a look around the car and couldn't see anything. All tyres look normal, certainly no visible signs of a puncture or blow out or anything. Felt for nails, nothing. So got in the car, reset the system and went for a quick drive again. Now nothing came on this time, which suggests the pressure isn't falling, or at least isn't falling quickly

Schoolboy error here, but I remember about 2 weeks ago I put the pressure up in my tyres as they were shockingly low when I got it (should be 2.1 and 2.3 bar, they were from 1.3-1.5 all around), but once I did the tyres up to the recommended pressure, I forgot in my noobness to do the Tyre pressure system reset that you should do. Could this be something to do with it? Seems a bit of a delayed reaction

If it is a genuine alert, could it be normal for me not to visibly notice any damage or change to the tyres? I will get it checked out after work but obviously before Christmas, a nice run flat bill is not what I want :(
 
My 5 series does this every so often if I forget to check the tire pressures for a while. If there's no sign of a puncture, it probably just means that one (or more) of the tyres is low.

Check, top-up to manufacturer recommended pressures and reset the i-Drive pressure monitor. Will probably be OK after that :)
 
The tyre pressure warning light can be triggered if you go over a nasty pothole/speedbump however, it sounds like it was an isolated thing as, if your tyres were low, surely the light would stay on?

First thing i would do is check the tyre pressures with a tyre pressure gauge. If all is well, it is likely to be an anomally in the system or possibly a tyre pressure sensor. I wouldn't worry about it for now unless one of your tyres is particularly low.

Tonight, i would suggest getting all of the tyres to the correct pressure and then resetting the TPC system and just wait and see.
 
Gaygle said:
The tyre pressure warning light can be triggered if you go over a nasty pothole/speedbump however, it sounds like it was an isolated thing as, if your tyres were low, surely the light would stay on?
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IIRC it works (atleast on the less recent BMWs) by detecting a reduction in the frequency of wheel rotations or something like that. So once it's reset, it will take the reduced frequency as "normal", and will only activate again once the pressure goes even lower.
 
Cheers for the advice guys

Yeah made a schoolboy error by resetting the system as it won't alert me any more as it will consider it normal

Will see what happens tonight, fingers crossed

If it does need replacing I'll be ditching it and replacing all 4 corners with Kumho KU31s as its £258 for 4 or £130 for 1 run flat! And I know at least the 2 back ones will need replacing in 3-4 months too
 
Steedie said:
If it does need replacing I'll be ditching it and replacing all 4 corners with Kumho KU31s as its £258 for 4 or £130 for 1 run flat!
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Please don't do this. Buy some better tyres. If you want budget decent tyres at least go for the Falken FK452's but you'd be better off finding the extra pennies for some Bridgestone Potenzas, Goodyears or perhaps some Continental SportContact 2's.

I know the KU31's are all the rage at the moment amongst the older Jap owners but the problem with user reviews especially those from people running cars on tighter budgets is you can never seperate how much of the rave comes from the fact they cost 10p..

You'll also need to buy a BMW Mobility pack once you've dumped the runflats incase you get a flat. You can get them for £130 from the dealer - electric pump and the tyre weld stuff and the everything you need to make it work.
 
Oh I was under the impression they were good tyres? I certainly didn't go for them because of cost, just because I've heard good things, especially on one of the BMW forums

Someone recommended the SportContact 2's, but when I looked online they didn't seem to get all that good a review.

What are you running right now Fox?

The Sport Contact 2's aren't much more than the Kumhos, £12 a corner in it after 4 wheel discount so will go for those if thats what you suggest

Site I'm using and it's review ON CSC2's - Getting a really bad review compared to cheaper tyres, especially on wear and grip? Maybe I should be using a different site for reviews
 
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Steedie said:
Oh I was under the impression they were good tyres? I certainly didn't go for them because of cost, just because I've heard good things, especially on one of the BMW forums

Someone recommended the SportContact 2's, but when I looked online they didn't seem to get all that good a review.

What are you running right now Fox?

The Sport Contact 2's aren't much more than the Kumhos, £12 a corner in it after 4 wheel discount so will go for those if thats what you suggest
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What's the tyre size? I'm sure the Kumho's are fairly decent, but what (i think) Fox is saying is that they're not proven tyres, like the Potenza RE050A, Eagle F1, Sport Contacts, Vredstein Ultrac Sessanta.

Might as well go for a set of one of the above tbh. They're proven, they're well and truly premium quality tyres and probably aren't THAT much more expensive than the Kumho's.
 
I do not trust user reviews on tyres because you dont know what they are being compared against. I could, and would, tell you the tyres I use are amazing and rate them highly for everything. Do you trust me? Should you? How should I know anyway? Have I run them back to back with the competition? Nope.

CSC2's are very highly rated though normally amongst those who buy M3's etc from new - ask a 7 year old M3 owner what tyres he likes best and he probably won't say CSC2's if you get my point..

I make my own mind up using a combination of user feedback *and* impartial, objective tests but even then I accept thats not perfect. Buying tyres is a pain.

As for your other question I use Goodyear Eagle F1 Assymetric on my 530i, and I've also replaced the Runflats on the Z4 with them all round as well.
 
Steedie said:
Oh I was under the impression they were good tyres? I certainly didn't go for them because of cost, just because I've heard good things, especially on one of the BMW forums

Someone recommended the SportContact 2's, but when I looked online they didn't seem to get all that good a review.

What are you running right now Fox?

The Sport Contact 2's aren't much more than the Kumhos, £12 a corner in it after 4 wheel discount so will go for those if thats what you suggest

Site I'm using and it's review ON CSC2's - Getting a really bad review compared to cheaper tyres, especially on wear and grip? Maybe I should be using a different site for reviews
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TBH ditch (pun unintended) the user review tyre sites. Everyone thinks they have the best tyre ever, but in reality 99.9% of people aren't nearly qualified enough for their opinions to be valid. Not to mention the tyres won't have been used on the same car, in the same size, in the same conditions and in the same driving style. That's why Tyre Tests are good (Evo, Autocar etc). They have qualified professionals giving their opinions on the tyres in controlled conditions - much more reliable.
 
Remember that human psychology is an interesting thing and people are often motivated more by price than anything else even if they dont realise it. This is why Kumhos etc are popular. They are considerably cheaper and if people can rationalise with themselves that they are 'good' then they'll buy them to save cash. Then when they've got them they find themselves reminding themselves that they bought 'good' tyres not that just went for 'cheaper' tyres.

The human mind is a fickle thing as you could make the same point about people who buy expensive tyres. It takes a very honest soul to drop 600 quid on a set of crud tyres and then tell the world they bought... crud tyres.
 
Well no, dont just rush out and buy those just because I've said they are good. I might be a complete halfwit when it comes to rating tyres! Do a bit of research :)

From a purely objective standpoint though the results of last years Evo Performance Tyre test were, IIRC:

1) Eagle F1 Assymetric
2) Vredstien Ultra Sessenta
3) Bridgestone Potenza RE050A

So really any of those will be fine. Falken FK452's seem to be getting far too much good press these days for it just to be down to price so worth thinking about. I've only ever seen them in one test - it was an issue of Wheels magazine in Australia where they won but unfortunately where compared to a load of crud tyres mostly.
 
Sorry Gaygle, wasn't ignoring you, tiny window (hiding at work :p) plus just refreshing means I only see the last post! Yeah the tyre review sites seem so dodgy, literally all the top tyres get slated on there, and always on 'wear' and 'buy again', the latter I'd imagine being due to cost. So I'm sticking with proper sites now as suggested

I've got 205/55/16s at the moment

Babybmw rave about the Falkens, but they also rave about the Kumhos. Also seen the Goodyears mentioned on there a few times from a quick search

What about Michelin? I basically want something that's going to last me a good while but still allow me to drive hard when I want to. Michelin are supposed to be the top guys when it comes to wear and grip aren't they? Looking at Michelin Pilot Exalto 2's, £316 a set but that's not too bad
 
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Pilot Exaltos seem to be very highly rated amongst the Clio chaps with the 182's etc.

Good tyres wear quickly - to get grip you have a softer tyre compound and obviously this wears out faster.

Maybe now is a good opportunity to upgrade to some 17 inch wheels? You'll get a better choice of tyres and it'll look better. You have quite high profile wheels. Swapping from runflats on these is going to reduce some of the steering feel and make the car a bit more... I dunno, squidgy? :p
 
Someone recommended going to 225/55 on all corners

I'd love to get bigger wheels. Unfortunately I can't really afford them, that will be about £600 for a good set wouldn't it? Then the cost of the tyres on top. Any other time of the year I'd take the hit, Christmas sort of puts a block on that :(
 
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